Double-acting pressure sensor

Abstract

A pressure sensor includes a base having a bottom wall and a first sidewall enclosed with the bottom wall to form a first receiving space. A pressure sensitive film is located in the first receiving space and the peripheral portion of the pressure sensitive film is arranged on the first sidewall. An elastic cover has a top wall, a second sidewall, and a protrusion. The top wall and the second sidewall are enclosed to form a second receiving space. The second sidewall is located on the first sidewall of the base, the protrusion extends from the top wall to the second receiving space and makes contact with the pressure sensitive film, transferring an external pressure to the pressure sensitive film. The resistance of the pressure sensitive film is virtually linear corresponding to the external pressure.

What is claimed is: 
     
       1. A pressure sensor comprising
 a base including a bottom wall and a first sidewall, the bottom wall and the first sidewall cooperatively forming a first receiving space, the first sidewall having a top portion facing away from the bottom wall; 
 a pressure sensitive film having a peripheral portion arranged on the top portion of the first sidewall such that the pressure sensitive film is suspended over the bottom wall, the pressure sensitive film having a resistance changed in a linear variation range within a pressure range; and 
 an elastic cover including a top wall, a second sidewall, and a protrusion, the top wall and the second sidewall form a second receiving space, wherein the second sidewall is positioned on the first sidewall of the base, the protrusion extends from the top wall to contact the pressure sensitive film so that a force from the external pressure is transferred to the pressure sensitive film, whereby the resistance of the pressure sensitive film changes in the linear variation range. 
 
     
     
       2. The pressure sensor of  claim 1 , wherein the height of the protrusion is larger than the height of the second sidewall. 
     
     
       3. The pressure sensor of  claim 1 , wherein the thickness of the pressure sensitive film is less than 1 mm. 
     
     
       4. The pressure sensor of  claim 1 , wherein the pressure sensitive film is selected from one of the stainless sheet, metal alloy epoxy film, silver epoxy film, silicone film, graphite film, carbon nanotube film, or epoxy resin film. 
     
     
       5. The pressure sensor of  claim 1 , wherein the pressure sensitive film further comprises a strained resistance wire. 
     
     
       6. The pressure sensor of  claim 5 , wherein the strained resistance wire of the pressure sensitive film is made of silver nano wire, conductive polymers, carbon nanotube, or graphene. 
     
     
       7. The pressure sensor of  claim 5 , wherein the strained resistance wire of the pressure sensitive film has a multiple waveform shape. 
     
     
       8. The pressure sensor of  claim 5 , wherein the linear variation range of the resistance for the strained resistance wire of the pressure sensitive film is within a range of 10 6  ohms-10 3  ohms. 
     
     
       9. The pressure sensor of  claim 1 , wherein the pressure sensor further comprises an adhesive to bond the second sidewall and the first sidewall. 
     
     
       10. The pressure sensor of  claim 9 , wherein the adhesive is selected from one of epoxy resin, hybrid epoxy resin, glue, or a mix of the above.